Electronic circuit device including metallic member having installation members

ABSTRACT

Bumps are formed on electrodes of semiconductor elements, and moreover, the semiconductor elements with the bumps are electrically connected to metallic members having installation members, whereby wiring lines are eliminated. Stray inductance and conduction resistance resulting from wiring lines can be reduced. A conventional dented connector and a projecting connector are eliminated by connecting the installation members to a second circuit board, thereby enabling an electronic circuit device of a power control system to be made compact.

This application is a National Stage of PCT/JP02/00167 filed Jan. 15,2002.

TECHNICAL FIELD

The present invention relates to an electronic circuit device of a powercontrol system using semiconductor elements such as IGBTs (InsulatedGate Bipolar Transistors), diodes and the like, for driving motors, anda method for manufacturing the electronic circuit device.

BACKGROUND ART

Lately, a working current in a motor driving device has increased inaccordance with an enhancement in performance and function of electronicdevices used in the motor driving device, thereby requiringsemiconductors to be used to meet a high current. A motor driving deviceused conventionally is shown in FIG. 16. An example of this conventionalmotor driving device will be described below with reference to FIG. 16.

In FIG. 16, reference numerals respectively indicate: 1 a an IGBT; 1 b adiode; 3 a high temperature solder; 4 a metallic element; 5 a sealingresin; 6 a solder; 7 a circuit board; 10 a heat radiation plate; 10 a aprojecting screw bed; 11 a screw; 12 a surface mounting electroniccomponent (passive element); 13 a surface mounting electronic component(semiconductor element); 14 a metallic base circuit board; 15 a siliconegrease; 18 a metallic wire; 19 a metallic lead; 22 a projectingconnector; 23 a dented connector; and 24 an insulation resin.

A method for manufacturing this thus-constituted conventional motordriving device will be discussed hereinbelow.

Semiconductor components such as the IGBT 1 a, the diode 1 b and thelike are connected by the high temperature solder 3 to metallic elements4. The IGBT 1 a and the diode 1 b, and these semiconductor componentsand metallic lead 19, are electrically joined together with use of themetallic wire 18. An aluminum wire or a gold wire is normally used asthe metallic wire 18. In using a metallic wire 18 formed of, e.g.,aluminum, the metallic wire 18 is connected to a second electrode of oneof these semiconductor components by performing wedge bonding of thealuminum wire. The second electrode is present opposite to a firstelectrode of this semiconductor component, which is joined to themetallic element 4. The second electrode of the semiconductor componentis formed of aluminum. Oxide films of aluminum on surfaces of both thesecond electrode and the metallic wire 18 are removed when the secondelectrode and the metallic wire are pressed into contact with each otherwith an ultrasonic energy being applied thereto in an ordinarytemperature state. The second electrode and the metallic wire 18 arethus joined. The metallic wire 18 joined to the second electrode of theone semiconductor component is routed to the metallic lead 19 obtainedby plating copper with tin, and is joined to the metallic lead 19 byperforming a wedge bonding method.

Thereafter, for a purpose of physically protecting the one semiconductorcomponent and the metallic wire 18, and improving reliability, thesemiconductor component 1 and the metallic wire 18 are coated and sealedwith the sealing resin 5 by performing a transfer molding technique orinjection molding technique. The metallic lead 19 is bent and cut bymolds to be even with the metallic element 4. During this sequence ofprocedures, an electronic component named “TO-220” comprising the onesemiconductor component, the high temperature solder 3, the metallicelement 4, the metallic wire 18, the metallic lead 19 and the sealingresin 5 is completed.

After a solder paste is printed onto the metallic base circuit board 14,various components such as the above electronic component “TO-220”, theprojecting connector 22, and the like are placed on the metallic basecircuit board. The metallic base circuit board 14 in its entirety is putinto a heating furnace, whereby the solder paste is melted. The solderpaste is then set by being returned to an ordinary temperature. This setsolder 6 electrically and physically joins the metallic base circuitboard 14 to various electronic components such as the electroniccomponent “TO-220”, the projecting connector 22, and the like.

For providing electrical insulation, the sealing resin 24 is applied tothe metallic base circuit board 14 in its entirety. The metallic basecircuit board 14, with the various electronic components, is put into areduced pressure furnace to remove bubbles mixing inside the sealingresin 24, and then put into a heating furnace to set the sealing resin24.

Next, the silicone grease 15 is applied to the heat radiation plate 10.The metallic base circuit board 14 is brought into intimate contact withthe heat radiation plate 10 and fixed by screws. Then, by inserting theprojecting connector 22 into the dented connector 23 after registeringthe projecting connector 22 mounted on the metallic base circuit board14 with the dented connector 23 mounted on the circuit board 7, thecircuit board 7 is brought into intimate contact with the projectingscrew bed 10 a and fixed by screws 11.

In the manner as above, the process of mounting to the metallic basecircuit board 14 electronic components which include electroniccomponents “TO-220” for switching a motor driving current and requiringheat radiation, and the process of combining the circuit board 7including the circuit for controlling the electronic components “TO-220”and requiring no heat radiation, are completed.

The above-described arrangement generates a loss caused by a resistanceof metallic wires 18 and metallic leads 19 and also a stray inductancebecause of a length of the wires 18 and leads 19. In addition, forexample, since the electronic component “TO-220” is equipped with ametallic lead 19, a larger area than an area of the electronic component“TO-220” is required for the metallic base circuit board 14, therebyimpeding miniaturization and high-density mounting.

Meanwhile, a motor driving device for electric products alike has beenrequired to be made compact and highly efficient in terms of heatradiation to meet a recent trend towards lighter, thinner, shorter andsmaller construction of electric products. However, when bubbles arepresent inside the high temperature solder 3, the bubbles obstruct heattransfer generated by a semiconductor component, thereby increasing aresistance from the semiconductor component to the metallic element 4.As a result, only a bubble part becomes high in temperature, which leadsto breakage of the semiconductor component 1 in a worst case.

As described hereinabove, the metallic wire 18 is joined to the secondelectrodes of semiconductor components by performing a wedge bondingmethod with the aluminum wire. In the conventional art, the metallicwire 18 is limited in thickness due to this joining method, and at thesame time the metallic wire 18 is limited in length due to anarrangement of substrate electrodes, thereby making it impossible toreduce a wiring resistance. Coping with an on-state resistance decreasein consequence of recent progress of semiconductor components is thushindered, with an imposing problem of noise increase resulting fromelectrical signals' requirement of a high frequency and a large current.

SUMMARY OF THE INVENTION

The present invention is devised to solve the above problems and has forits essential object to provide an electronic circuit device which iscompact, has good heat radiation efficiency and can reduce resistanceand stray inductance, and provide a method for manufacturing theelectronic circuit device.

In order to accomplish this objective, an electronic circuit device isprovided according to a first aspect of the present invention, whichcomprises:

a semiconductor element requiring heat radiation and having electrodesformed on opposite faces thereof;

a first circuit board electrically connected via a metallic plate to afirst electrode of the electrodes formed on one of the opposite faces ofthe semiconductor element, on which circuit board the metallic plate andthe semiconductor element are placed;

a second circuit board arranged on a side of the other of the oppositefaces of the semiconductor element so as to be opposite to the firstcircuit board, and having a control circuit for the semiconductorelement; and

a metallic wire for directly electrically connecting to each other asecond electrode, of the electrodes present on the other of the oppositefaces, and the second circuit board.

The above metallic wire may be formed to include a first bend portionfor absorbing expansion and contraction of the first circuit board andthe second circuit board resulting from heat radiation of thesemiconductor element.

The metallic wire joined to the second electrode may be extended in athickness direction of the semiconductor element.

The electronic circuit device may be constituted to further include aheat radiation member with supporting members for receiving the firstcircuit board thereon and supporting the second circuit board. Themetallic wire may be provided with a second bend portion for absorbing,in a state with the second circuit board being supported by thesupporting members, expansion and contraction of the first circuit boardand the second circuit board resulting from heat radiation, and forpressing the first circuit board against the heat radiation member.

An electronic circuit device of a power control system according to asecond aspect of the present invention comprises:

a semiconductor element requiring heat radiation and having firstelectrodes and second electrodes respectively formed on opposite facesthereof;

bumps formed on the second electrodes; and

a metallic member having a first face arranged opposite to the firstelectrodes so as to be electrically connected to the first electrodes,and including installation members formed of a metal erected on thefirst face, along a thickness direction of the semiconductor element, toa height which exceeds a height of the bumps in the thickness directionwhen the semiconductor element with the bumps is placed on the firstface.

Three or more installation members may be provided for one metallicmember in the above electronic circuit device of the second aspect.

The electronic circuit device of the second aspect may further include asecond circuit board which is arranged on a side opposite to that of thefirst electrodes so as to be electrically connected to the bumps andleading ends of the installation members, and is provided with a controlcircuit for the semiconductor element.

Also, the above electronic circuit device of the second aspect mayfurther include a heat radiation member with supporting members forreceiving the metallic member thereon via an electric insulating member,and dissipating heat conducted from the semiconductor element to themetallic member.

According to a third aspect of the present invention is provided amethod for manufacturing an electronic circuit device having:

a semiconductor element requiring heat radiation and having firstelectrodes and second electrodes respectively formed on opposite facesthereof;

bumps formed on the second electrodes; and

a metallic member having a first face arranged opposite to the firstelectrodes so as to be electrically connected to the first electrodes,and including installation members formed of a metal erected on thefirst face, along a thickness direction of the semiconductor element, toa height which exceeds a height of the bumps in the thickness directionwhen the semiconductor element with the bumps is placed on the firstface,

wherein the method comprises:

bringing the first face of the metallic member and the first electrodesinto contact with each other, placing the semiconductor element on thefirst face, and heating the semiconductor element;

supplying a molten solder to the first face;

relatively pressing the semiconductor element and the metallic member toremove bubbles from inside the molten solder present between the firstface and the first electrodes; and

decreasing a temperature of the molten solder while maintaining apressing state, thereby solidifying the molten solder and joining thesemiconductor element and the metallic member to each other.

In the manufacturing method of the third aspect, after joining of thesemiconductor element and the metallic member, the method furtherincludes a step of electrically connecting the bumps and leading ends ofthe installation members to a second circuit board which is arranged ona side of the other face and is provided with a control circuit for thesemiconductor element,

wherein, when a plurality of the metallic members are attached to thesecond circuit board, heights of the installation members of themetallic members may be adjusted to unify all the metallic members interms of height with respect to the second circuit board.

As described hereinabove, the electronic circuit device according to thefirst aspect of the the present invention is provided with the metallicwire for directly electrically connecting the second electrode formed onthe other of the opposite faces of the semiconductor element and thesecond circuit board arranged on the side of the other opposite face.Since the conventional dented connector and projecting connector can beeliminated, the electronic circuit device can be made compact.

Moreover, when the metallic wire is provided with the bend portion, thebend portion can absorb expansion and contraction between the firstcircuit board and the second circuit board resulting from heat of thesemiconductor element.

Since the metallic wire is extended in the thickness direction of thesemiconductor element, the electronic circuit device can furthermore beminiaturized.

When the metallic wire is extended in the thickness direction of thesemiconductor element and is further provided with the second bendportion, not only miniaturizing the electronic circuit device andabsorbing expansion and contraction can both be achieved, but the firstcircuit board can be pressed against the heat radiation plate, so thatheat can be stably removed.

In the electronic circuit device according to the second aspect of thepresent invention, the semiconductor element! is provided with the bumpson the second electrodes and metallic member having installationmembers, so that wiring lines are eliminated. Consequently, strayinductance and conduction resistance resulting from wiring lines can bereduced.

In the case where a plurality of the metallic members are provided, theheight of the metallic members can be made uniform by being adjusted bythe installation members.

Since the semiconductor element and the second circuit board can bedirectly electically connected to each other by providing the metallicmember, the conventional dented connector and projecting connector areeliminated, thus making the electronic circuit device small in size.When the heat radiation member is provided to support the second circuitboard, heat from the metallic member can be stably dissipated by the oneheat radiation member.

According to the manufacturing method for the electronic circuit devicein the third aspect of the present invention, the solder between thesemiconductor element and the metallic member is solidified after thesemiconductor element and the metallic member are relatively pressedagainst each other so as to remove bubbles from inside the solder.Therefore, thermal conduction from the semiconductor element to themetallic member will not be obstructed by bubbles, thus being able toprevent an abnormal temperature rise of the semiconductor element.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings in which:

FIG. 1 is a sectional view of a second circuit device as an electroniccircuit device of a power control system according to a first embodimentof the present invention;

FIG. 2 is a diagram of semiconductor elements constituting a firstcircuit unit in FIG. 1;

FIG. 3 is a diagram showing a state with bumps formed on thesemiconductor elements of FIG. 2;

FIG. 4 is a diagram showing a state in which the semiconductor elementswith bumps shown in FIG. 3 are mounted to a metallic member;

FIG. 5 is a diagram of a state having a sealing resin further providedto the state of FIG. 4;

FIG. 6 is a sectional view of a state in which the first circuit unit ofFIG. 5 is mounted to a second circuit board;

FIG. 7 is a sectional view of a state in which a plurality of the firstcircuit units are mounted to the second circuit board;

FIG. 8 is a sectional view of a second circuit device as an electroniccircuit device of a power control system according to a secondembodiment of the present invention;

FIG. 9 is a sectional view of a modified example of the second circuitdevice of FIG. 8;

FIG. 10 is a sectional view of a second circuit device as an electroniccircuit device of a power control system according to a third embodimentof the present invention;

FIG. 11 is a sectional view of a modified example of the second circuitdevice of FIG. 10;

FIG. 12 is a sectional view of a second circuit device as an electroniccircuit device of a power control system according to a fourthembodiment of the present invention;

FIG. 13 is a sectional view of a modified example of the second circuitdevice of FIG. 12;

FIG. 14 is a sectional view of a second circuit device as an electroniccircuit device of a power control system according to a fifth embodimentof the present invention;

FIG. 15 is a sectional view of a modified example of the second circuitdevice of FIG. 14; and

FIG. 16 is a sectional view of a conventional electronic circuit deviceof a power control system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before description of the present invention proceeds, it is to be notedthat like parts are designated by like reference numerals throughout theaccompanying drawings.

Electronic circuit devices according to the preferred embodiments of thepresent invention and a method for manufacturing the electronic circuitdevices will be described below with reference to the drawings.

First Embodiment

FIG. 5 shows a first electronic circuit device of a power control system(referred to as “a first circuit unit” hereinbelow) 100 which is oneexample of an electronic circuit device of this embodiment. FIG. 1 showsa second electronic device of a power control system (referred to as “asecond circuit device” below) 101 including first circuit units 100,which corresponds to another example of an electronic circuit device.

The second circuit device 101 of FIG. 1 is constituted as follows. 111is a drive semiconductor element which is used in a control system forcontrolling a driving current to a driving device, e.g., a motor or thelike and which requires a heat radiation treatment. The drivesemiconductor element includes an IGBT (Insulated Gate BipolarTransistor) 111-1 and a diode 111-2. As shown in FIG. 3, the drivesemiconductor element 111 has a first electrode 111 c and secondelectrodes 111 d formed on opposite faces 111 a and 111 b, respectively.112 are bumps (projecting electrodes) formed on the second electrodes111 d of the drive semiconductor element 111. 114 is a metallic memberwhich radiates and diffuses heat generated from the drive semiconductorelement 111 as shown in FIG. 4. An entire surface of the metallic member114 is plated with tin after projecting parts corresponding toinstallation members 114 b, to be described later, are formed fromcopper as a base material with use of molds. The metallic member 114 hasa first face 114 a, arranged opposite to the first electrode 111 c, tobe electrically connected to the first electrode 111 c. 113 is a hightemperature solder for joining the first electrode 111 c of the drivesemiconductor element 111 and the first face 114 a of the metallicmember 114 to each other. The aforementioned installation members 114 bare projected from the first face 114 a parallel to a thicknessdirection 111 e of the drive semiconductor element 111, and have aheight to exceed the bumps 112 in the thickness direction 111 e when thedrive semiconductor element 111, with the bumps 112 thereon, is placedonto the first face 114 a. Although the installation members 114 b of apair are formed in the embodiment, three or more installation memberscan be formed for one first circuit unit 100. If three or moreinstallation members are formed, a flatness of the first circuit unit100, when mounted to a second circuit board 116, can be further improvedas will be described later.

As indicated in FIG. 5, 115 is a sealing resin for protecting the drivesemiconductor element 111 and the bumps 112, which is applied to thedrive semiconductor element 111, mounted together with the bumps 112, tothe first face 114 a to such a level that nearly half a height of thebump 112 is exposed in the thickness direction 111 e. The first circuitunit 100 is constituted in the above-described manner.

As is shown in FIG. 6, the first circuit unit 100 is electricallyconnected, with the bumps 112 and leading ends 114 c of the installationmembers 114 b, through a solder 117 applied thereto to the secondcircuit board 116 arranged at a side of the face 111 b of the drivesemiconductor element 111.

As shown in FIG. 1, the second circuit board 116 includes a controlcircuit for the drive semiconductor element 111, with passive electroniccomponents 122, such as a capacitor, a resistor and the like, and activeelectronic components 123, such as a transistor, a memory, and the like,constituting the control circuit mounted to one face or to both faces ofthe second circuit board. Internal wirings 124 are provided in thesecond circuit board 116 to electrically connect the electroniccomponents 122 and 123 to the drive semiconductor element 111.

A heat radiation member 120, on which the metallic member 114 is placed,dissipates heat transferred from the drive semiconductor element 111 tothe metallic member 114 into surrounding air. The heat radiation member120 also has, for instance, a recessed part 120 b as shown in FIG. 1formed by supporting members 120 a which support the second circuitboard 116. The first circuit unit 100 is stored in the recessed part 120b, and both end parts of the second circuit board 116 are fixed byscrews 121 to the pair of the supporting members 120 a. An insulatingresin 119 of a high heat dissipation efficiency is applied, byperforming a heat press method, to a bottom face 120 c of the recessedpart 120 b so as to conduct heat from the metallic member 114 to theheat radiation member 120, and at the same time electrically insulatethe metallic member 114 and the heat radiation member 120 from eachother. Moreover, a silicone grease 118 is filled between the insulatingresin 119 and the metallic member 114 to decrease heat resistance at acontact portion between the metallic member 114 and the insulating resin119. Since a height of the metallic member 114 is specified as will bediscussed later, the silicone grease 118 works as a buffer to press themetallic member 114 towards the insulating resin 119, thereby bringingthe metallic member 114 and the insulating resin 119 into intimatecontact with each other at all times. A soft sheet may be used in placeof the silicon grease 118.

The second circuit device 101 is constituted as above.

A process of forming the above first circuit unit 100 will be describedwith reference to FIGS. 2-6.

Referring to FIG. 3, gold plating bumps 112 are formed on secondaluminum electrodes 111 d of the drive semiconductor element 111 of FIG.2 with use of a projecting electrode forming machine which is animproved wire bonding apparatus, or with use of plating. Then as shownin FIG. 4, in a state in which the drive semiconductor element 111 isplaced at a predetermined position on the first face 114 a of themetallic member 114, the drive semiconductor element 111 and themetallic member 114 are put into a high temperature furnace heated to350° C., in which a reducing atmospheric state in a mixed atmosphere ofnitrogen and hydrogen is maintained. Molten high temperature solder 113is supplied, specifically by being dropped according to the embodiment,onto the first face 114 a of the metallic member 114 in the hightemperature furnace. As a consequence, the first face 114 a of themetallic member 114 and the first electrode 111 c of the drivesemiconductor element 111 are joined by the high temperature solder 113.

After the high temperature solder 113 is supplied, the drivesemiconductor element 111 and the metallic member 114 are relativelypressed against each other to remove bubbles from inside the moltensolder present between the first face 114 a and the first electrode 111c. The metallic member 114 is pressed parallel to the drivesemiconductor element 111 so as to bring the metallic member 114intointimate contact with the drive semiconductor element 111. With anabsolute contact state maintained, the metallic member 114 and the drivesemiconductor element 111 are cooled to solidify the solder 113. Themetallic member 114 and the drive semiconductor element 111 are returnedto air after this solidification.

Next in FIG. 5, the sealing resin 115 is formed to mechanically protectthe drive semiconductor element 111 itself and joining portions betweenthe drive semiconductor element 111 and the bumps 112. The sealing resin115 is applied in a liquid state and set by heating, or formed by atransfer molding or an injection molding technique. The first circuitunit 100 is formed during this process.

Subsequently, for protecting the drive semiconductor element 111 andenabling the drive semiconductor element 111 to be handled as anelectronic component, the first circuit unit 100 is joinedsimultaneously to the electronic components 122 and 123 on the secondcircuit board 116 with use of the solder 117 as shown in FIG. 6. Anormally used surface mounting technique (SMT) is employed for thisjoining.

In the present embodiment as discussed hereinabove, the metallic member114 is provided with installation members 114 b of metal which projectfrom the first face 114 a of the metallic member 114 in the thicknessdirection 111 e of the drive semiconductor element 111. Accordingly, anelectric connection between the first electrodes 111 c of the drivesemiconductor element 111 and the second circuit board 116 can beachieved through the installation members 114 b, and moreover, themetallic member 114 with the drive semiconductor element 111 can befixed to the second circuit board 116 through the installation members114 b. Since a conventionally required dented connector 23 andprojecting connector 22 are hence eliminated, the first circuit unit 100and the second circuit device 101 can be made compact in size. At thesame time, since the second electrodes 111 d of the drive semiconductorelement 111 are electrically connected to the second circuit board 116via the bumps 112, a stray capacity can be reduced in comparison withconventional art which uses metallic wires 18 and metallic leads 19, anda resistance can be decreased.

Since wiring resistance is reduced by this joining via the bumps 112 ascompared with the conventional art, reduction of on-state resistance andnoise is enabled.

As above, bubbles are removed from inside the solder 113 by relativelypressing the first electrode 111 c of the drive semiconductor element111 and the metallic member 114 against each other to join the same.Thus, the drive semiconductor element 111 is prevented from abnormallyoverheating because of voids.

FIG. 7 shows a state in which a plurality of first circuit units 100 arejoined to the second circuit board 116 upon completion of procedures inFIGS. 2-5. Although two first circuit units 100 are installed in FIG. 7,needless to say, there may be installed three or more units, or incontrast one unit may be installed. In a case where the plurality of thefirst circuit units 100 are installed, an error range of heights H1 andH2 of the first circuit units 100, as measured from the second circuitboard 116, should be maintained within a specified value. While themetallic member 114 has the installation members 114 b, a height of theinstallation members 114 b of each of the metallic members 114 can beadjusted by, e.g., cutting the installation members 114 b, whereby apositional accuracy with an error range of within ±50 μm can be realizedfor the heights H1 and H2.

The second circuit device 101 shown in FIG. 1 is a combination of thesecond circuit board 116, in a state of FIG. 7, and the heat radiationmember 120. The second circuit device 101 naturally exerts the sameeffects as those of the first circuit unit 100.

Second Embodiment

A fourth circuit device 103 as a modified example of the second circuitdevice 101 will be described with reference to FIG. 8.

The fourth circuit device 103 includes a third circuit unit 102 which isa modified example of the above first circuit unit 100. Referencenumeral 133 of FIG. 8 indicates a first circuit board formed of a metal.Single-sided surface mounting is performed for the second circuit board116 in FIG. 8.

The third circuit unit 102 has spring wires 136 of a metal and a secondmetallic member 134 respectively attached in place of the bumps 112 andthe metallic member 114 of the first circuit unit 100. Each spring wire136 is a conductor for electrically connecting the drive semiconductorelement 111 and the second circuit board 116 to each other, and has asecond bend portion 136 a as indicated in FIG. 8. In the fourth circuitdevice 103 of FIG. 8, one end of each spring wire 136 penetrating thesecond circuit board 116 is soldered to the second circuit board 116.The second metallic member 134 has no installation member 114 b. Thesecond bend portion 136 a of each spring wire 136 is not resin sealed bysealing resin 115.

The third circuit unit 102 is constituted the same in other points asthe above-described first circuit unit 100.

The third circuit unit 102 of the above constitution has the secondmetallic member 134 joined to the first circuit board 133 by solder 117.The first circuit board 133 is placed on heat radiation member 120 viasilicone grease 118.

In the fourth circuit device 103 constituted as above, the first circuitboard 133 can be pressed by the second bend portions 136 a of the springwires 136 to the heat radiation member 120, and moreover, a thermalstress can be absorbed by the spring wires 136, so that a highreliability is realized.

Since each of the spring wires 136 is arranged parallel to thicknessdirection 111 e and is not directed orthogonally to the thicknessdirection 111 e as illustrated, the fourth circuit device 103 is madecompact. Furthermore, since bubbles present in solder 113 between drivesemiconductor element 111 and the second metallic member 134 areeliminated, the drive semiconductor element 111 can be prevented fromabnormally overheating because of voids.

A fourth circuit device 103-1 shown in FIG. 9 is a modification of thefourth circuit device 103 of FIG. 8, in which spring wires 136-1 aresoldered to one face of second circuit board 116 without penetrating thesecond circuit board 116 as shown in FIG. 9. Double-sided mounting isprovided for the second circuit board 116. This modified fourth circuitdevice 103-1 is of the same constitution in other points as theabove-described fourth circuit device 103 indicated in FIG. 8.

The same effects as in the fourth circuit device 103 in FIG. 8 can alsobe obtained in the fourth circuit device 103-1 of FIG. 9.

Third Embodiment

A fifth circuit device 104 as a modified example of the second circuitdevice 101 will be depicted with reference to FIG. 10.

The fifth circuit device 104 has a constitution such that the projectingconnector 22 and the dented connector 23 are removed from the drivingdevice described with reference to FIG. 16, and a fresh metallic lead139 is connected to metallic wire 18. Operation of removing bubblesdescribed above is performed during soldering to join drivesemiconductor element 111 and second metallic member 134 to one another.Single-sided surface mounting is provided for the second circuit board116 in FIG. 8.

The metallic lead 139 is a metal wire having tin plating on copper,which is joined to aluminum metallic wire 18 subjected to wedge bondingof aluminum. A first bend portion 139 a is formed in a halfway portionof the metallic lead 139. One end of the metallic lead 139 is solderedafter passing through the second circuit board 116. Double-sidedmounting is performed for the second circuit board 116.

Since the projecting connector 22 and the dented connector 23 areeliminated and the metallic lead 139 is directly connected to the secondcircuit board 116, the fifth circuit device 104 can be made compact. Thefirst bend portion 139 a formed in the metallic lead 139 can absorbthermal stress, thereby realizing a high reliability. Further, sincebubbles are removed from inside solder 113 present between the drivesemiconductor element 111 and the second metallic member 134, the drivesemiconductor element 111 can be prevented from abnormally overheatingdue to voids.

A fifth circuit device 104-1 in FIG. 11 is a modification of the fifthcircuit device 104 of FIG. 10. A metallic lead 139-1 is, as shown inFIG. 11, soldered to one face of second circuit board 116 withoutpenetrating the second circuit board 116. The constitution of the fifthcircuit device 104-1 in other points is the same as that of theabove-described fifth circuit device 104 shown in FIG. 10.

The fifth circuit device 104-1 can obtain the same effects as in thefifth circuit device 104 shown in FIG. 10.

Fourth Embodiment

A sixth circuit device 105 as a modified example of the above fourthcircuit device 103 will be described below with reference to FIG. 12.

The sixth circuit device 105 is provided with metallic wires 141 inplace of the spring wires 136 in the fourth circuit device 103. Eachmetallic wire 141 has a gold ball 140 formed by melting a gold wire byusing an electric spark. Each gold ball 140 is joined to drivesemiconductor element 111 or the like. Joining of the gold balls 140 isexecuted by performing a wire bonding technique through heating andultrasonically vibrating the gold wires. After this joining, eachmetallic wire 141 is pulled up in a thickness direction 111 e, cut to apredetermined length and sealed by the sealing resin 115 to be preventedfrom deformation. One end of each metallic wire 141 passing through thesecond circuit board 116 is soldered. The constitution of other pointsof the sixth circuit device is the same as that of the fourth circuitdevice 103 described earlier and shown in FIG. 8.

According to the sixth circuit device 105, similar to the fourth circuitdevice 103, since the metallic wires 141 extend in the thicknessdirection 111 e, the sixth circuit device 105 can be made compact.Moreover, since bubbles are removed from inside solder 113 presentbetween the drive semiconductor element 111 and second metallic member134, the drive semiconductor element 111 can be prevented from abnormaloverheating because of voids.

A sixth circuit device 105-1 in FIG. 13 is a modification of the sixthcircuit device 105 in FIG. 12, wherein metallic wires 141-1 are solderedto one face of second circuit board 116 without being passed through thesecond circuit board 116, as is clear from FIG. 13. The sixth circuitdevice 105-1 is constituted the same in other points as is the sixthcircuit device 105 described above.

The sixth circuit device 105-1 of FIG. 13 can obtain the same effects asthe effects of the sixth circuit device of FIG. 12.

Fifth Embodiment

Referring to FIG. 14, a seventh circuit device 106 as a modified exampleof the fourth circuit device 103 will be depicted herein.

The seventh circuit device 106 uses metallic wires 142 of, e.g.,aluminum or copper. The metallic wires 142 are joined to drivesemiconductor element 111 or the like by performing a wedge bondingtechnique with ultrasonic vibration applied. Each metallic wire 142after being so joined is pulled up in a thickness direction 111 e, cutto a predetermined length and sealed by sealing resin 115 to beprevented from deformation. One end of each metallic wire 142,penetrating through second circuit board 116, is soldered. The seventhcircuit device 106 is constructed the same in other points as theabove-described fourth circuit device 103 shown in FIG. 8.

According to the seventh circuit device 106, similar to the fourthcircuit device 103, since the metallic wires 142 extend in the thicknessdirection 111 e, the seventh circuit device 106 can be formed compact insize. Also, since aluminum or copper is used for the metallic wires 142,the seventh circuit, device 106 can be constructed inexpensively ascompared with the case of using gold wires. Additionally, a process ofremoving bubbles prevents the drive semiconductor element 111 from beingabnormally overheated.

The seventh circuit device 106 in FIG. 14 is modified by way of exampleto a seventh circuit device 106-1 shown in FIG. 15. As indicated in FIG.15, metallic wires 142-1 are soldered to one face of second circuitboard 116 without penetrating the second circuit board. The modifiedseventh circuit device 106-1 is of the same constitution in other pointsas the aforementioned seventh circuit device 106.

The seventh circuit device 106-1 of FIG. 14 can obtain the same effectsas the seventh circuit device 106 shown in FIG. 13.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

1. An electronic circuit device comprising: a semiconductor elementhaving a first surface and a second surface, with said first and secondsurfaces facing in opposite directions; a first electrode on said firstsurface; a second electrode on said second surface; a bump on saidsecond electrode; a metallic member having metal installation membersextending from a first face of said metallic member; and a circuit boardelectrically connected to said bump and to leading end parts of saidmetal installation members, said circuit board having a control circuitfor said semiconductor element, wherein said first face of said metallicmember is electrically connected to said first electrode such that saidmetal installation members extend from said first face to a level beyonda level at which said bump is positioned.
 2. The electronic circuitdevice according to claim 1, wherein said semiconductor element requiresheat radiation therefrom, and further comprising: a heat radiationmember connected to said metallic member via an electric insulatingmember, said heat radiation member for dissipating heat from saidsemiconductor element to said metallic member.
 3. The electronic circuitdevice according to claim 2, wherein said heat radiation member includessupporting members.
 4. The electronic circuit device according to claim3, wherein said circuit board is connected to said supporting members.5. The electronic circuit device according to claim 4, wherein saidmetallic member is between supporting members.
 6. The electronic circuitdevice according to claim 3, wherein said metallic member is betweensaid supporting members.